Electronic musical instrument capable of generating tone signals having the pitch frequency, tone color and volume envelope varied with time

ABSTRACT

In response to a pitch determining voltage obtained by key operation, a voltage controlled oscillator generates a tone signal having a pitch frequency corresponding to the note of the operated key. The tone signal, after a tone color is imparted by a voltage controlled filter, is supplied to a voltage controlled amplifier. The voltage controlled oscillator, voltage controlled filter and voltage controlled amplifier are controlled, during key depression and key release times, by control voltage waveforms varied with time. This causes the pitch, tone color and envelope of the tone signal to be transiently varied. An electronic musical instrument according to this invention may be constituted either as a monophonic type having a single voltage controlled oscillator or as a polyphonic type having a plurality of voltage controlled oscillators by using a key assigner.

United States Patent Hiyoshi June 3, 1975 [54] ELECTRONIC MUSICAL INSTRUMENT 3,571,481 3/1971 Adachi 84/1.13

CAPABLE OF GENERATING TONE 2 233232 3 53: 23 SIGNALS HAVING THE PITCH 3'614288 |0I|97| Am fn'iijijiiiiii1:13:31 FREQUENCY, TONE COLOR AND VOLUME 3,626,078 12/1971 Sekiguchi ENVELOPE VARIED WITH TIME 3,767,833 10/1973 Noble et a1. 3,786,166 l/l974 M' d I75] Term Hamammsui Japan 3,801,721 4 1974 aiifi zr 84/].19 [73] Assignee; Nippon Gakkl seizo Kab shiki 3,828,110 8/1974 Colin 84/11 Kaisha, Hamamatswshi, Japan R27,983 4/1974 Stearns 84/101 [221 Filed: 1974 Primary ExaminerStephen .l. Tomsky 2 Appl 462 39 Assistant Examiner-Stan1ey .l. Witkowski Attorney, Agent, or FirmFlynn & Frishauf [30] Foreign Application Priority Data [57] ABSTRACT 2 japan f In response to a pitch determining voltage obtained by 973 Japan 43 45430 key operation, a voltage controlled oscillator gener- 973 Japan 48'45431 ates a tone signal having a pitch frequency correapan sponding to the note of the operated key. The tone signal, after a tone color is imparted by a voltage con- [52] US. Cl. 84/126, 84/l. 1;i/% ;/Gl.l29d trolled filter, is Supplied to a voltage controlled ampli 51 I t Cl Glob no? Glob 5 fier. The voltage controlled oscillator, voltage con- 84/ l 094 n trolled filter and voltage controlled amplifier are con- 1 l gi' 'l I 2 trolled, during key depression and key release times, l d 6 by control voltage waveforms varied with time. This causes the pitch, tone color and envelope of the tone signal to be transiently varied. An electronic musical 156] References cued instrument according to this invention may be consti- UNITED STATES PATENTS tuted either as a monophonic type having a single volt- 3,288,904 II/I966 George 84/1.0l age controlled oscillator or as a polyphonic type hay. 3,288,909 201061111 a plurality of voltage controlled oscillators 3,538,804 11/1970 eorge k 3,557,295 l/l97l Adachi usmg a ey asslgner 3,570,357 3/1971 Adachi 84/126 13 Claims, 12 Drawing Figures ISI 1? 1:1 I? sgf gg vco VCF VCA AMF. fi e I I a I g 17 CONTROL CONTROL CONTROL ER E Q \GIEINTAGE gghTAGE XEINTAGE TRIGGER A A SIGNAL KEYBOARD J42 PARAMETER CONTROLLING 20 SECTION VOLTAGE GENERATOR PATENTEDJUH3 I975 SHEET FIG.

EXPRESSION CONTROL PITCH DETERMINING TRIGGER SIGNAL TO CONT. VOL. GEN.

F I G. 2

KEYBOARD SECTION Ig P M fl A 0 LE 2 A WM TT .A I H W NLN G OOE N CVG rI. mm T 8I TA I G NR F RA OE C TT .A CN v mum CVG w FII. a MA m mm. 0 RA A0 C TIT DIV V NLN 00E CVG K m I1 RUI Q I EL M GA D M IM R R.@ N m 1. m EE VIN DG EE HA KS T L HO PV (2ND DECAY TIME KEY RELEASED ATTACK LEVEL SUSTAIN LEVEL CUTOFF LEVEL 7 X A KEY DEP IST DECAY TIME TTACK TIME RESSED PAI'ENIEDIIIIIG I975 B QQQG SHEET 2 F 4 CONSTANT vOLTAGE 26 SOURCE 29 VOLTAGE 5 CONTROLLED sCHMITT OSCILLATOR I I 2 2 TRIGGER 3O 23 5 P VOLTAGE HIGH IN UT IMPEDANCE ESRJRIENTER BUFFER OUT I JTZZ 28 PITCH DETERMINING CONTROL vOLTAGE FROM VOLTAGE KEYBOARD sECTION 34 TONE 313 g 358 9 32 CURRENT 3-BUFFER AMP. CONTROLLED i 8 VCO REsIsTOR g8 N +?%I LED VOLTAGE FILTER I; SSJCURRENT REACTOR 37 3 CONVERTER L I HIGH INPuT IMPEDANCE g gg j- I REsIsTOR 9 CONTROL 0 VOLTAGE CONTROL PITCH DETERMINING vOLTAGE FROM KEYBOARD SECTION} F G 6 47 34 IN PHASE 49 TONE 42 g gg IL 4 I @FER R I'ZE AMP IQTONE sIGNAL VCF J whXg OUTPUT vOLTAGE 48 CONTROLLED 33%??- -46 AMPL'F'ER CONVERTER L45 CONTROL VOLTAGE TRIGGER SIGNAL FROM KEYBOARD SHEET 3 OUT OUT (O FACTOR) CONTROL vOLTAGE X2 HIG INPUT GENERATOR Q 15;

IMPEOANGE AMP.

5 /52 55s 5 ---XI VOLTAGE 1; vOLTAGE vOLTAGE CONTROL -x2 CONTROLLED *CONTROLLED -GONTROLLEO T$EQUENCE L 3 RESISTOR RESISTOR RESISTOR PULSE GEN. X

*x4 I I J, I L XI x3 x4 vOLTAGE vOLTAGE T g LED CON ROLLED vOL AGE SOURCE SOuRcE .J Lu LU 2 5 5 a Z A A R S S E 6 J 6 8 E 6 LU 4 Yb S a e 4 0 d O we wf 1 g 2 I t g G z 1 9 N 0 %ROI %\RO2 R03 R04 ROS R06 R0? fl PARAMETER GONTROLLING VOLTAGE GENERATOR 2 Q ELECTRONIC MUSICAL INSTRUMENT CAPABLE OF GENERATING TONE SIGNALS HAVING THE PITCH FREQUENCY, TONE COLOR AND VOLUME ENVELOPE VARIED WITH TIME BACKGROUND OF THE INVENTION This invention relates to an electronic musical instrument and more particularly to an electronic musical instrument having a voltage controlled oscillator for gen erating, in response to a pitch determining voltage obtained by key operation, a tone signal having a pitch frequency corresponding to the note of the operated key.

With a conventional electronic musical instrument, tone signals corresponding to a plurality of keys are obtained by tone generators having master oscillators and frequency dividers for sequentially frequency-dividing the outputs of the oscillators. The tone signals are supplied selectively to tone coloring filters through key operation, thereby forming a tone color. With such electronic musical instruments, therefore, the tone signal derived from the tone generators by key operation has the same pitch frequency during the key operation; i.e., its tone pitch is not varied from the rise to the decay of the tone signal. The tone color imparted by the tone coloring filters during the key operation is all of the same nature. For this reason the musical sounds so obtained are inevitably monotonous.

SUMMARY OF THE INVENTION It is accordingly the object of this invention to provide an electronic musical instrument capable of causing the tone pitch and tone color of the tone signal obtained by key operation to be varied or modulated with time during the key depression and key release times.

According to one embodiment of this invention there are provided a single voltage controlled oscillator and a first control voltage generator for controlling the oscillation frequency of the voltage controlled oscillator. To the voltage controlled oscillator there are supplied a pitch determining voltage corresponding to any one of keys operated at a keyboard section and a control voltage formed by the first control voltage generator in response to a trigger signal showing the operation of the key, and varied with time during key depression and key release times. For this reason, the pitch frequency of that tone signal corresponding to the note of the operated key which is formed by the voltage control oscillator is transiently modulated. The output tone signal from the voltage controlled oscillator is supplied to a voltage controlled filter where a tone color is imparted to the tone signal. The voltage controlled filter has its cutoff frequencies transiently controlled during the key depression and key release times by a control voltage from a second control voltage generator which is varied with time, and consequently an output from the filter undergoes a tone color modulation. The output tone signal of the voltage controlled filter is fed to a voltage controlled amplifier. The voltage controlled amplifier has its gain controlled by a control voltage from a third control voltage generator which is varied with time during the key depression and key release times, and consequently an envelope according to the control voltage waveform is imparted to the output of the voltage controlled amplifier. The voltage controlled amplifier is normally in a cutoff condition and is operated upon receipt of the control voltage to allow the passage of a signal and therefore functions as a keyer. The first, second and third control voltage generators generate, in response to various parameter controlling voltages from a parameter controlling voltage generator, control voltages having desired parameters. The control voltage waveforms from the first and second control voltage generators have such parameters as an initial level, attach level, normal level, attack time, i.e., time interval from the initial level to the attack level as involved during the key depression time, first decay time, i.e., time interval from the attack level to the normal level, and a second decay time, i.e., time interval from the normal level to the initial level as involved during the key release time; and these parameters are controlled by the parameter controlling voltage generator. The control voltage waveform of the third control voltage generator has such parameters as a cutoff level, sustain level, attack time, i.e., time interval from the cutoff level to the attack level as involved during the key depression, first decay time, i.e., time interval from the attack level to the sustain level, and second decay time, i.e., time interval from the sustain level to the cutofi level as involved during the key release; and these parameters are controlled by the parameter controlling voltage generator.

According to another embodiment of this invention there are provided a plurality of musical tone signal producing circuits (less in number than the keys of a keyboard section) each including a voltage controlled oscillator, voltage controlled filter and voltage controlled amplifier; and a key assigner adapted to permit, upon operating a plurality of keys at a time, pitch determining voltages corresponding to these keys to be supplied to the respective musical tone signal producing circuits according to the order of the operated keys.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an electronic musical instrument according to one embodiment of this invention;

FIG. 2 is a circuit arrangement of a keyboard section of FIG. 1;

FIG. 3 shows the waveforms of control voltages applied to the voltage controlled oscillator, voltage controlled filter and voltage controlled amplifier of FIG. 1;

FIG. 4 is a block diagram showing one example of the voltage controlled oscillator of FIG. 1;

FIG. Sis a block diagram showing one example of the voltage controlled filter;

FIG. 6 is a block diagram showing one example of the voltage controlled amplifier of FIG. 1;

FIG. 7 is a schematic view of parameter controlling voltage generator, and control voltage generator for voltage controlled oscillator and voltage controlled filter;

FIG. 8 is a schematic view of parameter controlling voltage generator and control voltage generator for voltage controlled amplifier;

FIG. 9 is a block diagram of an electronic musical instrument according to another embodiment of this invention;

FIG. 10 is a circuit arrangement of a key assigner of FIG. 9;

FIG. 11 shows a modification of the electronic musical instrument; and

FIG. 12 is an explanatory view showing the operation of the modification of FIG. 11. i

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows one embodiment of this invention. In the drawing a reference numeral 11 shows a voltage controlled oscillator (hereinafter referred to as VCO). VCO 11 generates, in response to a pitch determining voltage signal obtained by key operation at a keyboard section 12, a tone signal having a pitch corresponding to the note of the operated key. The tone signal from VCO 11 is coupled to a voltage controlled filter (hereinafter referred to as VCF), where a tone color is imparted to the tone signal, and then to a voltage con trolled amplifier 14 (hereinafter referred to as VCA). The output of VCA 14 is fed through an output amplifier 15 to a loudspeaker 16. Control voltage generators 17 to 19 are provided to control the pitch, tone color and tone volume of the tone signal and coupled to VCO 1 1, VCF 13 and VCA 14, respectively. Control voltage generators 17 to 19 generate, in response to a trigger signal obtained by the key operation at the keyboard section 12, voltage signals having a variety of parameters set at a parameter controlling voltage generator 20, thereby controlling VCO l1, VCF 13 and VCA 14 respectively. In FIG. 1, and throughout the drawings, the thick arrows coupling blocks together represent a plurality of signal lines. VCO 11 is adapted to frequencyvary, according to a voltage waveform from the control voltage generator 17, a predetermined frequency signal corresponding to an operated key, VCF 13 has its cutoff frequency characteristic varied according to a voltage waveform from the control voltage generator 18', and VCA 14 has its amplification gain controlled according to a voltage waveform of the control voltage generator 19 to vary the envelope of an output tone signal therefrom.

FIG. 3 shows the graphical representation of control voltage waveforms A and B, differing in voltage level, obtained from the control voltage generators 17 to 19. In FIG. 3, waveform, A shows the control voltage waveform generated by control voltage generators l7 and 18 and applied to VCO 11 and VCF 13 and waveform B shows the control voltage waveform generated by control voltage generator 19 and applied to VCA 14. When the key is depressed, the voltage waveform A rises, during an attack time, from an initial level to an attack level and then decays, during a first decay time, from the attack level to a normal level. The normal level is continued until the key is released. After release of the key, the voltage waveform further decays, during a second decay time, from the normal level to the initial level.

When the voltage waveform A is fed to VCO 11, a tone signal is so controlled that its frequency abruptly varies during the key depression time from the initial level frequency somewhat lower than the normal level frequency to the attack level frequency somewhat higher than the normal level frequency. Thereafter, the tone signal frequency approaches, during the first decay time, to the normal level frequency which is determined by the pitch determining voltage from the keyboard section 12. After lapse of the first decay time, the tone signal frequency becomes equal to the normal level frequency. After release of the key, the tone signal frequency decays, during the second decay time, from the normal level frequency to the initial level frequency. That is, the tone signal frequency obtained from VCO 11 is modified according to the voltage waveform which is varied with time.

When the voltage waveform A is supplied to VCF 13, the cutoff frequencies of the voltage control filter is controlled in accordance with the waveform and, consequently, the tone color of the one signal is modified.

A voltage waveform B rises, upon depression of the key, from a cutoff level to a peak level. After lapse of the attack time, the voltage waveform is returned, during the first decay time, to a sustain level, and the sustain level is continued until the key is released. After release of the key, the voltage waveform decays, during the second decay time, from the sustain level to the cutoff level. When the voltage waveform B is supplied to VCA 14, such an envelope as is shown in the waveform B is imparted to the tone signal. When no voltage waveform B is applied to VCA I4, VCA 14 is in the cutoff state. It will be understood that VCA I4 is operated as a tone keyer.

FIG. 2 shows the arrangement of the keyboard section 12 from which a pitch determining voltage is supplied to VCO 1 1. The voltage of a power source E is divided by a voltage dividing circuit arrangement including resistors R, and the normally open fixed contacts of key switches S1, S2, S3, are connected to the respective voltage dividing points. The movable contacts of the respective key switches are connected to the normally closed fixed contacts of the adjacent key switches. When a plurality of keys are depressed at a time, a voltage of the voltage dividing point connected to the key switch actuated by only one key and having a magnitude corresponding to the key is fed to VCO 11 in the key switch arrangement shown. There are further provided key switches S01, S02, S03 which are ganged with the key switches S01, S02, S03 respectively. When the key is operated, a trigger signal whose voltage is lowered from a power source voltage E1 to zero volt is supplied to the control voltage generators 17 to 19. The control voltage generators 17 to I9 start the formation of control voltages upon receipt of the trigger signal.

FIG. 4 shows the detailed arrangement of VCO 11. A pitch determining voltage applied from the keyboard section 12 to an input terminal 21 is stored in a capacitor 22, and then after passage through a high input impedance buffer 23 added to a control voltage applied from the control voltage generator 17 through an input terminal 24 by means of mixing resistors. The added voltage is converted, at a voltage-current converter 25, into a current signal. A typical voltage-current converter 25 comprises, for example a conventional transistor amplifier whose output current is a function of the input voltage applied thereto. An output current of the converter 25 charges a capacitor 27 connected to a constant voltage source 26. The voltage of the capacitor 27 is applied through a buffer 28 to a Schmitt trigger 29. When the voltage of the capacitor 27 reaches a predetermined voltage value, the Schmitt trigger 29 is operative to render a transistor 30 conductive, causing the capacitor 27 to be discharged. An oscillation output of saw-tooth wave is delivered from an output terminal 31 by the repeated charge and discharge of the capacitor 27. The charging speed of the capacitor 27 is varied according to the magnitude of output current of the converter 25. Consequently, oscillation frequency is controlled by the pitch determining voltage from the keyboard section 12 and the controlled voltage from the control voltage generator 17.

FIG. 5 shows the detailed arrangement of VCF 13. A tone signal from an input terminal 32 is applied through a buffer amplifier 33 to a current controlled resistor 34. The current controlled resistor 34 is constituted by a diode, etc., and controlled by an output current of a voltage-current converter 35 which receives, via mixing resistors a control voltage from a control terminal 36 together with a pitch determining voltage received at a terminal 91, charged in a capacitor 92 and passed through a high input impedance buffer 93. The resistor 34 determines, together with a reactance element 37 (e.g., a capacitor), the cutoff frequency of the filter (e.g., an LPF). A tone color imparted tone signal is obtained, through an amplifier 38, from an output terminal 39. A Q control input supplied to a control terminal 40 controls a voltage-controlled resistor 41, thereby controlling the feedback amount of the amplifier 38 (constituting and active filter) and thus the Q factor of the filter.

FIG. 6 shows the detailed arrangement of VCA 14. A tone signal from an input terminal 42 is supplied through a buffer amplifier 43 to a differential amplifier 44. The gain of the differential amplifier 44 is controlled by the output current of a voltage to current converter 46 which receives a control voltage from a control voltage generator 19 through a control terminal 45. The output signals of the differential amplifier 44 are supplied though an in-phase amplifier 47 and a phase inverting amplifier 48 to an output terminal 49 through mixing resistors. In both the outputs of the differential amplifier 44, the tone signal is included in an opposite phase relationship and a direct current component is included in an in-phase relationship. Consequently, only the tone signal is derived from the output terminal 49.

FIG. 7 shows the detailed arrangement of the control voltage generators l7 and 18 and parameter controlling voltage generator 20. The pitch control voltage generator 17 and tone color control voltage generator 18 are identical in their arrangement, except that the latter has a Q factor control. The parameter controlling voltage generator 20 has potentiometers R01, R02, R03 R07. R01 has a general level controlling voltage coupled to a control terminal R02 has an attack level controlling voltage coupled to a control terminal b; R03 has an initial level controlling voltage coupled to a terminal 0; R04 has an attack time controlling voltage coupled to a terminal d; R has a first decay time controlling voltage coupled to a terminal e; R06 has a second decay time controlling voltage coupled to a terminal f; and R07 has a Q factor controlling voltage coupled to a terminal g. A voltage controlled voltage source 50 generates, in response to the attack level controlling voltage, a voltage of a magnitude corresponding to the attack level. A typical controlled voltage source 50 comprises, for example, a power source coupled to a voltage divider which may include an FET. The output voltage of the voltage source 50 is supplied through a voltage controlled resistor 51 such as a controlled F ET to a capacitor 52. Upon receipt of a trigger signal from the keyboard section 12, a control Sequence pulse generator generates a control output X1. The voltage controlled resistor 51 becomes operative to cause the capacitor 52 to be charged by the output voltage of the voltage source 50 in response to the control output X1 and its resistance determining a charging time constant is determined according to the magnitude of the attack time controlling voltage. The charging voltage of the capacitor 52 is derived through a high input impedance buffer amplifier 54 and compared with the output voltage of the voltage source 50 by a comparator 55. When the magnitude of charging voltage of the capacitor 52 reaches the magnitude of output voltage of the voltage source 50, i.e., the capacitor 52 is charged up to the attack level, the comparator 55 generates an output X2. The control sequence pulse generator 53 then generates a control output X3 upon receipt of the output X2. A voltage controlled resistor 56 becomes operative to create a discharging path of the capacitor 52 in response to the controlled output X3 and its resistance determining a discharging time constant, i.e., the first decay time is determined according to the magnitude of the first decay time controlling voltage. Upon release of the key at the keyboard section the control sequence pulse generator 53 generates a control output X4. In response to the control output X4 the capacitor 52 is discharged, through a voltage controlled resistor 57, down to the initial level, i.e., the level of output voltage of a voltage controlled voltage source 58 which is obtained in accordance with the magnitude of the initial level controlling voltage. The discharging time constant, i.e., the second decay time is dependent upon the resistance of the voltage controlled resistor 57 which is determined according to the magnitude of the second decay time controlling voltage. The so varying voltage of the capacitor 52 and the general level of the potentiometer R01 are added together via mixing resistors to form a control voltage waveform at output terminal 59 as shown in FIG. 3A. The potentiometer R07 causes a Q factor control voltage to be generated at an output terminal 60. The Q factor control voltage is coupled to a control terminal 40 of VCF of FIG. 5. The sliders of potentiometers may be provided on the control panel of an electronic musical instrument so as to be easily adjusted by a player.

FIG. 8 shows the detailed arrangement of the envelope control voltage generator 19. The parameter controlling voltage generator 20 has potentiometers R08, R09, R010, R011 and R012 coupled to control terminals h, i,j, k and 1, respectively, which generate voltages for controlling parameters such as general level, sustain level, attack time, first decay time and second decay time. Upon receipt of a trigger signal from the keyboard section 12, a control sequence pulse generator 61 generates a control output X1. A voltage controlled resistor 62 is operated in response to the control output X1. As a result, a capacitor 63 is charged up to a peak level with an attack time, i.e., time constant dependent upon the resistance of the voltage controlled resistor 62 which is determined according to the magnitude of the attack time controlling voltage. The voltage of the capacitor 63 is derived through a high input impedance amplifier 64. When the voltage of the capacitor 63 reaches the level, a comparator 65 generates a control output X2. The control sequence pulse generator 61 then generates a control output X3 upon receipt of the control output X2. in response to the control output X3 the capacitor 63 is discharged, through a voltage controlled resistor 67 down to the sustain level, i.e., the level of output voltage of a voltage controlled voltage source 66 which is determined according to the magnitude of the sustain level controlling voltage. The

resistance of the resistor 67, which determines a discharging time constant, is controlled by the magnitude of the first decay time controlling voltage. Upon release of the key, a control output X4 is obtained and the capacitor 63 is discharged through a voltage controlled resistor 68. The resistance of the voltage controlled resistor 68, which determines a discharge time constant, is controlled by the second decay time controlling voltage. The so varying voltage of the capacitor 63 and the general level controlling voltage from the potentiometer R08 are added together via mixing resistors to form the control voltage waveform at output terminal 67 as shown in FIG. 3B.

FIG. 9 shows, unlike the embodiment of FIG. 1, an embodiment capable of producing a plurality of tone signals by operating a plurality of keys at a time. In FIG. 9 the same reference numeral is employed to indicate parts or elements corresponding to those shown in FIG. 1 and further explanation is therefore omitted. There are provided, for example, five sets of musical tone signal producing circuitry 70A, 70B, 70C, 70D and 70E each having VCO 11, VCF 13, VCA l4 and control voltage generators 17 to 19. The control voltage generators 17 to 19 of the musical tone signal producing circuitry 70A, 70B, 70C, 70D and 70E simultaneously receive various parameter controlling voltages from the parameter controlling voltage generator 20. The outputs of the musical tone signal producing circuitry 70A to 70E are coupled to an output terminal 71.

Corresponding to the five sets of musical tone signal producing circuitry 70A to 7015, there is provided a key assigner 72 having five sets of key assigner circuitry 72A to 72E. Each key assigner circuitry has key assigner circuits equal in number to the keys 76a, 76b, 76c and key switches 77a, 77b, 77c of the keyboard section 75. The key assigner circuitry 72A to 72E are operatively coupled to the key switches 77a, 77b, 77c and a pitch determining voltage source 78 and have pitch determining voltage deriving common terminals 73A to 73E and trigger signal deriving common terminals 74A to 74E. The pitch determining voltage deriving terminals 73A to 73E are each coupled to VCO 11 and VCF 13 of the corresponding musical signal producing circuitry and the trigger signal deriving terminals 74A to 74E are coupled to the control voltage generators 17 to 19 of the corresponding musical tone signal producing circuitry. The key assigner 72 is, when a plurality of keys are operated at the keyboard section 75, operative to cause DC voltages of magnitudes corresponding to the notes of keys operated according to an operating sequence to be derived from the pitch determining voltage deriving output terminals 73A to 73E. When, for example, the keys 76 0, 76b and 76c are operated in this order, DC voltages of magnitudes corresponding to the notes of the keys 76a, 76b and 76c sequentially appear at the output terminals 73A, 73B and 73C. At the same time, trigger signals sequentially appear at the trigger signal deriving terminals 74A, 74B and 74C in response to the key operation. When the key 76a is released and the keys 76b and 76c are kept depressed, the pitch determining voltage of the output terminal 73A disappears, while the pitch determining voltages of the output terminals 733 and 73C remain. When, in this state, the other key is depressed, a pitch determining voltage of a magnitude corresponding to the note of its key appears at the terminal 73A.

FIG. 10 shows partially the circuit arrangement of the key assigner 72 shown in FIG. 9. Though, in the figure, assigner circuits are shown operatively connected only to the key switch 77c, it will be understood that the similar circuits are operatively coupled to the other key switches.

Output conductors 78a, 78b, 78c connected to the voltage dividing points of the pitch determining voltage source 78 extend into the key assigner 72 and, for example, the output conductor 78c is coupled, through relay switches 81A to 81E respectively driven by relays A to 80E, to output terminals 73A to 73E of the key assigner circuitry 72A to 72E. A circuit for driving the relay 80A included in the key assigner circuitry 72A has a p-n-p type transistor 01A and n-p-n type transistors 02A and (BA. The collector of transistor Q3A is connected to the relay 80A and the base of an n-p-n type transistor 04A. The collector of transistor 01A and emitter of transistors 02A and 03A are connected to that emitter of transistor 04A which is grounded through the key switch 77 c. The collector of transistor 01A is connected to the anode of a diode D1A, while the collector of transistor 04A is con nected to the cathode of diode DlA. The emitter of transistor Q1A is coupled, together with the emitters of transistors 01A associated with the other key switches of the assigner circuitry 72A, to the trigger signal deriving terminal 74A through a delay circuit 82A. In the other key assigner circuitry 72B to 72D there are provided diodes DlB to DID and transistors 048 to 04D corresponding to the diode DlA and transistor Q4A, in addition to transistors (MB to 033, QIC to Q3C and QlD to 03D (all not shown), respectively, connected in the same manner as the transistors 01A to 03A so as to drive the relays 80B to 80D. The emitter collector paths of the transistors 043 to 04D are sequentially connected in series with the emitter collector path of the transistor 04A. In the key assigner circuitry 725 are provided only transistors QlE to 03E for driving the relay 80E. The emitter of transistor 03E is connected to the collector of transistor Q4D in the key assigner 72D. The emitters of transistors 013 to 01E of the assigner circuitry 72B to 72E are coupled through delay circuits 82B to 82E to the trigger signal deriving terminals 74B to 74E respectively.

There will be explained the operation of the circuit arrangement of FIG. 10.

Suppose that, out of the key switches 77a, 77b, 77c only the key switch 77c is actuated. In this case there is created a ground circuit of the transistors 01A to 04A operatively coupled to the key switch 770 in the assigner circuitry 72A. As a result, the transistor 01A is rendered conductive and then the transistor Q2A connected, in a positive feedback relation, to the transistor QlA is rendered conductive. This causes the emitter potential of the transistor QZA to be raised to permit the transistor 03A to be conductive and the transistor 04A to be nonconductive. Conduction of the transistor QBA causes the relay 80A to be energized to permit the contact 31A to be closed. Thus, a pitch determining voltage on the conductor 780 is coupled to the output terminal 73A. Conduction of the transistor QlA also causes the emitter potential drop of the transistor QlA to be induced. The potential drop is transmitted through the delay circuit 82A to' the output ter minal 74A to cause a trigger signal to be generated. In response to the pitch determining voltage and trigger signal on the terminals 73A and 74A, the musical tone signal producing circuitry 70A forms a musical tone signal corresponding to the note of the key 76c. Since the transistor 04A is nonconductive, those assigner circuits of the other assigner circuitry 728 to 72E associated with the key switch 77c are not operated due to the prevention of formation of their ground circuit. Consequently, the relays 808 to 80E are all unoperative.

Next suppose that any one of the key switches 77a, 77b 77c except for the key switch 77c is actuated. As will be apparent from the foregoing explanation, a DC voltage of a magnitude corresponding to the note of the actuated key and a trigger signal are generated at the output terminals 73A and 74A of the assigner circuitry 72A having a first priority order. When, in this state, the key switch 7 7c is actuated, the transistor 01A is not rendered conductive since its emitter is at a lower potential. Consequently, the transistors QZA and Q3A are not rendered conductive and the relay 80A is not driven. When the transistor 03A is rendered nonconductive, then the transistor 04A is rendered conductive. This causes a ground circuit of the transistors 01B to Q4B (not shown) in the assigner circuitry 728 to be created to permit the relay 808 to be operated. A pitch determining voltage of a magnitude corresponding to the note of the key 760 is generated at the output terminal 73B and at the same time a trigger signal showing the actuation of the key switch 77c appears at the terminal 748. Since, in this state, the transistor 04B of the assigner circuitry 728 is nonconductive, the relays 80C to 80E are all unoperative. When, with the key switch 77c being actuated, the other actuated key is released,

the emitter potential of the transistor QlA is raised so that both the transistors QlA and 02A will tend to become conductive. Since, however, the emitter collector path of the transistor 01A is grounded through the diode DlA, transistor 04A and key switch 770, the transistor 02A and thus the transistor 03A can not become conductive. For this reason, the pitch determining voltage and trigger signal both obtained by actuating the key switch 77c continue to be drived from the output terminals 738 and 74B of the assigner circuitry 728. Suppose that pitch determining voltages and trigger signals are generated at the output terminals 73A to 73D and 74A to MD by actuating any four key switches except for the key switch 77c. When in this state the key switch 77c is actuated, a pitch determining voltage and trigger signal based on this actuation are obtained as will be understood from the foregoing explanation, from the output terminals 73E and 74E in the assigner circuitry 72E having a fifth priority order.

FIG. 11 shows an embodiment capable of imparting a portamento effect to a tone signal generated by VCO 11. This embodiment is similar to that shown in FIG. 4 with an addition of a resistor 87 and a switch 89. In this embodiment, a pitch determining voltage is coupled through a memory circuit or integration circuit 85 comprising a capacitor 22 and a resistor 87 and through a high input impedance buffer circuit 23. The time constant of the memory circuit 85 may be selected to be, for example, 3 to 4 seconds. A pitch determining voltage obtained through the operation of any key is stored in the capacitor 22 due to the presence of the voltage memory circuit 85. When in this state the other key is operated, a pitch determining voltage is supplied to the voltage memory circuit 85 and the voltage of the capacitor 22 is changed, according to the abovementioned time constant, into a new voltage value. Consequently, the output frequency of VCO 11 is gradually shifted from a note frequency corresponding to the previously operated key to a note frequency corresponding to the newly operated key, thereby providing a portamento effect.

Of course, where a plurality of VCO's are provided, as many voltage memory circuits as the VCO's are provided.

FIG. 12 shows the operation in case of a plurality of VCOs. When, in this case, the keys corresponding to notes C3, E3 and G3 are sequentially depressed for chord performance, VCO l, VCO 2 and VCO 3 oscillate at frequencies corresponding to the notes C3, E3 and G3, respectively, starting with the respective certain frequencies. Upon release of the keys corresponding to the notes C3, E3 and G3, pitch determining voltages corresponding to the notes C3, E3 and G3 are respectively stored in the corresponding voltage memory circuits. Next when the keys corresponding to notes C4, E4 and G4 are sequentially operated, VCO l, VCO 2 and VCO 3 oscillate at first at frequencies corresponding to the latest notes C3, E3 and G3, but their oscillation frequencies are gradually shifted, according to the time constant of the voltage memory circuit, into the frequency corresponding to C4, E4 and G4, respectively. A switch 89 shown in FIG. I1 is provided on a control panel of an electronic musical instrument so as to stop the generation of a portamento effect, as required, by shunting the resistor 87.

What is claimed is:

I. An electronic musical instrument comprising:

a keyboard section including means for generating in response to key operation a pitch determining voltage having a magnitude representing the note of any operated key and a trigger signal indicating the at least one of a depression and release operation of the key;

voltage controlled oscillator means coupled to said keyboard section for generating in response to the pitch determining voltage a tone signal having a pitch frequency corresponding to the note of the operated key;

voltage controlled filter means connected to the output of said voltage controlled oscillator means for imparting a tone color to the output signal of said oscillator means;

control voltage generating means for generating in response to the trigger signal from said keyboard section control voltages the amplitude values of which vary as a function of time, said control voltages being coupled to said oscillator means and filter means to control the oscillator frequency and frequency characteristics thereof respectively;

the control voltages from said control voltage generating means representing controlled parameters which include an initial level, normal level, attack level, attack time from the initial level to the attack level during a key depression time, first decay time from the attack level to the normal level, and second decay time from the normal level to the initial level during a key release time;

parameter controlling voltage generating means coupled to said control voltage generating means for controlling the parameters of the control voltages of said control voltage generating means; and

sound reproducing means connected to the output of said voltage controlled filter means.

2. An electronic musical instrument according to claim 1 further comprising voltage controlled amplifier means coupled to said voltage controlled filter means and connected between said voltage controlled oscillator means and said sound reproducing means; and

further control voltage generating means coupled to said keyboard and to said voltage controlled amplifier means for generating in response to the trigger signal from said keyboard a control voltage for controlling the gain of said voltage controlled amplifier means to thereby control the envelope of the tone signal.

3. An electronic musical instrument according to claim 1 further including a voltage memory circuit means coupled to said keyboard section for storing the magnitude of the pitch determining voltage which is coupled to said voltage controlled oscillator means.

4. An electronic musical instrument according to claim 3 in which said voltage memory circuit means comprises integrator circuit including a resistor coupled with a capacitor.

5. An electronic musical instrument according to claim 4 further comprising a switch means connected in parallel with said resistor.

6. An electronic musical instrument according to claim 2 in which the control voltage from said further control voltage generating means represents controlled parameters which include a sustain level, attack time from a cutoff level to an attack level during a key depression time, first decay time from the attack level to the sustain level, and a second decay time from the sustain level to the cutoff level during a key release time; and said parameter controlling voltage generating means being coupled to said further control voltage generating means for controlling the parameters of the control voltage of said further control voltage generating means.

7. An electronic musical instrument comprising: a keyboard section having a plurality of keys and a plurality of key switches actuated by the keys;

pitch determining voltage source means having output conductors equal in number to the number of said keys and generating pitch determining voltages having magnitudes representing the notes of said keys on said respective output conductors;

key assigner means operatively coupled to said keyboard section and to the output conductors of said pitch determining voltage means and having a plurality of first output terminals less in number than the number of said keys and a plurality of second output terminals equal in number to the number of said first output terminals, said key assigner means supplying, upon the operation of some of said keys at the same time, pitch determining voltages corresponding to the operated keys to said first output terminals according to the operated order, and supplying trigger signals representative of key operation to said second output terminals;

a plurality of musical tone signal producing circuit means each connected to the respective first and second output terminals of said key assigner means, said musical tone signal producing circuit means each including voltage controlled oscillator means coupled to a first output terminal of said key assigner means for generating in response to the pitch determining voltage on the first output terminal of said key assigner means a tone signal having a pitch frequency corresponding to the note of the operated key, voltage controlled filter means connected to the output of said voltage controlled oscillator means to impart a tone color to the output signal of said oscillator means, and control voltage generating means coupled to a second output terminal of said key assigner means for generating in response to the trigger signal on the second output terminal of said key assigner means control voltages whose amplitude values vary as a function of time, the control voltages being coupled to said oscillator means and filter means to control the oscillation frequency and the frequency characteristic thereof respectively; and

sound reproducing means connected to the output of said plurality of musical tone signal producing circuit means.

8. An electronic musical instrument according to claim 7 in which said musical tone signal producing means each further comprises voltage controlled amplifier means coupled to said voltage controlled filter means and connected between said voltage controlled oscillator means and said sound reproducing means; and further control voltage generating means coupled to said keyboard for generating in response to the trigger signal a control voltage the value of which varies as a function of time, said control voltage from said furter control voltage generating means being coupled to said voltage controlled amplifier means to control the gain thereof to thereby control the envelope of the tone signal.

9. An electronic musical instrument according to claim 7 in which said musical tone signal producing means each includes a voltage memory circuit means coupled to said key assigner means for storing the magnitude of the pitch determining voltage which is coupled to said voltage controlled oscillator means.

10. An electronic musical instrument according to claim 9 in which said voltage memory circuit means comprises an integrator circuit including a resistor cou pled with a capacitor.

11. An electronic musical instrument according to claim 10 further comprising a switch means connected in parallel with said resistor.

12. An electronic musical instrument according to claim 7 in which the control voltages from said control voltage generating means represent controlled parameters which include an initial level, normal level, attack level, attack time from the initial level to the attack level during a key depression time, first decay time from the attack level to the normal level, and second decay time from the normal level to the initial level during a key release time; and there is further provided parameter controlling voltage generating means coupled to said control voltage generating means for controlling said parameters of the control voltages of said control voltage generating means.

13. An electronic musical instrument according to claim 8 in which the control voltage from said further control voltage generating means represents controlled parameters which include a sustain level, attack time from a cutoff level to an attack level during a key depression time, first decay time from the attack level to the sustain level and second decay time from the sustain level to the cutoff level during a key release time; and there is provided parameter controlling voltage generating means coupled to said further control voltage generating means for controlling the parameters of the control voltage of said further control voltage generating means.

* i l k 

1. An electronic musical instrument comprising: a keyboard section including means for generating in response to key operation a pitch determining voltage having a magnitude representing the note of any operated key and a trigger signal indicating the at least one of a depression and release operation of the key; voltage controlled oscillator means coupled to said keyboard section for generating in response to the pitch determining voltage a tone signal having a pitch frequency corresponding to the note of the operated key; voltage controlled filter means connected to the output of said voltage controlled oscillator means for imparting a tone color to the output signal of said oscillator means; control voltage generating means for generating in response to the trigger signal from said keyboard section control voltages the amplitude values of which vary as a function of time, said control voltages being coupled to said oscillator means and filter means to control the oscillator frequency and frequency characteristics thereof respectively; the control voltages from said control voltage generating means representing controlled parameters which include an initial level, normal level, attack level, attack time from the initial level to the attack level during a key depression time, first decay time from the attack level to the normal level, and second decay time from the normal level to the initial level during a key release time; parameter controlling voltage generating means coupled to said control voltage generating means for controlling the parameters of the control voltages of said control voltage generating means; and sound reproducing means connected to the output of said voltage controlled filter means.
 1. An electronic musical instrument comprising: a keyboard section including means for generating in response to key operation a pitch determining voltage having a magnitude representing the note of any operated key and a trigger signal indicating the at least one of a depression and release operation of the key; voltage controlled oscillator means coupled to said keyboard section for generating in response to the pitch determining voltage a tone signal having a pitch frequency corresponding to the note of the operated key; voltage controlled filter means connected to the output of said voltage controlled oscillator means for imparting a tone color to the output signal of said oscillator means; control voltage generating means for generating in response to the trigger signal from said keyboard section control voltages the amplitude values of which vary as a function of time, said control voltages being coupled to said oscillator means and filter means to control the oscillator frequency and frequency characteristics thereof respectively; the control voltages from said control voltage generating means representing controlled parameters which include an initial level, normal level, attack level, attack time from the initial level to the attack level during a key depression time, first decay time from the attack level to the normal level, and second decay time from the normal level to the initial level during a key release time; parameter controlling voltage generating means coupled to said control voltage generating means for controlling the parameters of the control voltages of said control voltage generating means; and sound reproducing means connected to the output of said voltage controlled filter means.
 2. An electronic musical instrument according to claim 1 further comprising voltage controlled amplifier means coupled to said voltage controlled filter means and connected between said voltage controlled oscillator means and said sound reproducing means; and further control voltage generating means coupled to said keyboard and to said voltage controlled amplifier means for generating in response to the trigger signal from said keyboard a control voltage for controlling the gain of said voltage controlled amplifier means to thereby control the envelope of the tone signal.
 3. An electronic musical instrument according to claim 1 further including a voltage memory circuit means coupled to said keyboard section for storing the magnitude of the pitch determining voltage which is coupled to said voltage controlled oscillator means.
 4. An electronic musical instrument according to claim 3 in which said voltage memory circuit means comprises integrator circuit including a resistor coupled with a capacitor.
 5. An electronic musical instrument according to claim 4 further comprising a switch means connected in parallel with said resistor.
 6. An electronic musical instrument according to claim 2 in which the control voltage from said further control voltage generating means represents controlled parameters which include a sustain level, attack time from a cutoff level to an attack level during a key depression time, first decay time from the attack level to the sustain level, and a second decay time from the sustain level to the cutoff level during a key release time; and said parameter controlling voltage generating means being coupled to said further control voltage generating means for controlling the parameters of the control voltage of said further control voltage generating means.
 7. An electronic musical instrument comprising: a keyboard section having a plurality of keys and a plurality of key switches actuated by the keys; pitch determining voltage source means having output conductors equal in number to the number of said keys and generating pitch determining voltages having magnitudes representing the notes of said keys on said respective output conductors; key assigner means operatively coupled to said keyboard section and to the output conductors of said pitch determining voltage means and having a plurality of first output terminals less in number than the number of said keys and a plurality of second output terminals equal in number to the number of said first output terminals, said key assigner means supplying, upon the operation of some of said keys at the same time, pitch determining voltages corresponding to the operated keys to said first output terminals according to the operated order, and supplying trigger signals representative of key operation to said second output terminals; a plurality of musical tone signal producing circuit means each connected to the respective first and second output terminals of said key assigner means, said musical tone signal producing circuit means each including voltage controlled oscillator means coupled to a first output terminal of said key assigner means for generating in response to the pitch determining voltage on the first output terminal of said key assigner means a tone signal having a pitch frequency corresponding to the note of the operated key, voltage controlled filter means connected to the output of said voltage controlled oscillator means to impart a tone color to the output signal of said oscillator means, and control voltage generating means coupled to a second output terminal of said key assigner means for generating in response to the trigger signal on the second output terminal of said key assigner means control voltages whose amplitude values vary as a function of time, the control voltages being coupled to said oscillator means and filter means to control the oscillation frequency and the frequency characteristic thereof respectively; and sound reproducing means connected to the output of said plurality of musical tone signal producing circuit means.
 8. An electronic musical instrument according to claim 7 in which said musical tone signal producing means each further comprises voltage controlled amplifier means coupled to said voltage controlled filter means and connected between said voltage controlled oscillator means and said sound reproducing means; and further control voltage generating means coupled to said keyboard for generating in response to the trigger signal a control voltage the value of which varies as a function of time, said control voltage from said furter control voltage generating means being coupled to said voltage controlled amplifier means to control the gain thereof to thereby control the envelope of the tone signal.
 9. An electronic musical instrument according to claim 7 in which said musical tone signal producing means each includes a voltage memory circuit means coupled to said key assigner means for storing the magnitude of the pitch determining voltage which is coupled to said voltage controlled oscillator means.
 10. An electronic musical instrument according to claim 9 in which said voltage memory circuit means comprises an integrator circuit including a resistor coupled with a capacitor.
 11. An electronic musical instrument according to claim 10 further comprising a switch means connected in parallel with said resistor.
 12. An electronic musical instrument according to claim 7 in which the control voltages from said control voltage generating means represent controlled parameters which include an initial level, normal level, attack level, attack time from the initial level to the attack level during a key depression time, first decay time from the attack level to the normal level, and second decay time from the normal level to the initial level during a key release time; and there is further provided parameter controlling voltage generating means coupled to said control voltage generating means for controlling said parameters of the control voltages of said control voltage generating means. 